The present invention relates to the replacement of pre-placed prosthetic joints and, more particularly, is concerned with a method and apparatus for removing the cement mantle used to secure the pre-placed joint in place. In its more particular aspects, the invention is concerned with such a method and apparatus for removing the cement mantle to secure the ball of a prosthetic hip joint to the patient's femur.
Prosthetic hip and knee joints have become relatively commonplace. Unfortunately, however, there has also been a progressive rise in the incidence of the nonseptic failure of such joints which necessitates revision surgery to affect their replacement. The leading cause of the nonseptic failure of hip joints is the loosening of the femoral side of the prosthetic appliance. This is generally the result of loosening of the cement securing mantle for the appliance from the cavity in the femur within which the mantle is received.
Revision surgery for the replacement of a failed joint requires that both the prosthetic appliance and the mantle holding it in place within the bone cavity be removed. The old prosthetic device is usually easily removed using a slap-hammer, since its surface is smooth and separable from the underlying cement mantle. The the cement mantle, however, is tightly adherent to the surrounding bone and generally remains so adhered, even after the prosthetic device is removed. Removal of the adhered cement mantle is presently performed by progressively chipping the mantle away using a hammer and chisel. This method is tedious and the possibility of the chisel going past the mantle and fracturing the underlying bone is present. Other methods of removing the cement mantle, using powered drilling and boring devices, are similarly tedious and dangerous to the bone.
Prior revision surgery for the replacement of prosthetic hip joints also often includes a trochanteric osteotomy to remove the greater trochanter. Although this exposes the cement mantle and makes it easier to work upon, it generally does not eliminate the necessity for chipping the mantle away with a hammer and chisel to affect its removal.